1. Field of the Invention
The present invention relates to firearms, more particularly to a receiver assembly for a firearm.
2. Description of Related Art
The use of a receiver on a military style firearm is known. Typically, the receiver is configured to receive a magazine. Differences exist, however, in how the receiver functions and the type of magazine that the receiver can accept.
A major factor affecting the design of the receiver is the type of magazine. High capacity magazines were and are typically manufactured in one of two styles. One style relates to a magazine having a retaining feature and a locking feature. Thus, the first type of magazine can be referred to as a dual feature magazine. Examples of the first type include a tabbed magazine such as might be used on an AK-47 rifle. The other style relates to a magazine that does not use both a retaining and locking feature (i.e. a non-dual featured magazine). Due to differences in the geometry of the two different styles of magazine, two general methods of inserting the magazine into the receiver exist, depending on the style of magazine being used.
A first method of magazine insertion is to insert one end of a tabbed magazine into the receiver. The tab on the tabbed magazine catches on a tab engaging feature in the receiver and the tab is used as a pivot point for rotating the tabbed magazine into the receiver until a magazine catch engages a locking feature of the tabbed magazine. Thus, in the first method the tabbed magazine is held in the receiver well by the tab engaging feature engaging the tab (i.e., the retaining feature), by the magazine catch engaging the locking feature, and by the two walls of the receiver well.
A second method of magazine insertion is to insert a non-tabbed magazine into the receiver by sliding the non-tabbed magazine straight into the receiver well and using a magazine catch to engage a cutout in a wall of the non-tabbed magazine. Unlike the first method, in the second method there is no need to rotate or rock the magazine into the receiver well. Thus, the second method provides a simpler motion for inserting the magazine that can be beneficial when attempting to quickly insert the magazine in the firearm.
Once the magazine is inserted, the firearm can be discharged repeatedly until all the cartridges contained within the magazine are fired. After the last cartridge is fired, a bolt stop is pushed into a blocking position by a cartridge follower and the bolt stop prevents the bolt assembly from moving forward into the battery position. Once a new magazine has been inserted into the receiver, a bolt stop button can be activated. The bolt stop button retracts the bolt stop and allows the bolt assembly to move forward into the battery position, the bolt assembly stripping off a cartridge from the new magazine in the process. It would be preferable to allow ambidextrous operation of the bolt stop button.
Before the new magazine can be inserted, however, the old magazine must be removed. Two general methods exist for removing the magazine from the receiver, depending on whether the magazine is a dual featured magazine such as a tabbed magazine, or is a non-dual featured magazine. With a dual-featured magazine, a magazine release button is activated with the one hand and the dual-featured magazine is rotated out of the receiver with the other hand. Thus, the method of removing a dual-featured magazine requires two hands.
With a non-dual featured magazine, the magazine release button is activated with one hand and the non-dual featured magazine drops free of the receiver. Thus, with a non-dual featured magazine the removal of the empty magazine is a one hand operation. While the release is a one hand operation, the magazine release button is designed to be operated by either the right or left hand, thus limiting certain ergonomic aspects of a firearm, including the ability for the particular firearm to be readily used in either hand. As can be appreciated, however, the method of removing a non-dual featured magazine by simply pressing a button does have certain advantages. For example, the one handed release of a magazine is useful to individuals, whom for medical reasons, have trouble grasping the magazine with the off hand. In addition, the ability to quickly remove an empty magazine can decrease the overall time it takes to go from an empty magazine to a full magazine. Decreasing this transition time can be valuable to members of the armed forces engaged in hostile combat.
As previously mentioned, both tabbed and other style magazines were produced for use in appropriately designed receivers. Due to historical factors, the quantity of high capacity tabbed magazines currently in existence is greater than the quantity of high capacity magazines of other styles. Thus, the cost of high capacity magazines made in styles other then the tabbed style has risen because of the limited supply and the desirability of the magazine quick release feature. The cost of high capacity tabbed magazines, on the other hand, has remained relatively inexpensive. A receiver that accepts the high capacity tabbed magazine could provide the user of the firearm with a decreased operating cost.